Posttraumatic stress disorder (PTSD) is associated with increased arousal and exaggerated responses to potential threats. This study aims to determine whether individuals with PTSD perceive surprised faces as a potential threat. Surprise is an ambiguous emotion that can represent a positive or negative context. Previous studies have shown that individuals with PTSD show abnormal brain activation t... read moreo fearful and angry faces compared to control participants, which suggests that PTSD is associated with a heightened threat response to emotional facial expressions. Therefore, we hypothesized that individuals with PTSD would have an exaggerated threat response to surprised facial expressions compared to a trauma-exposed non-PTSD (TENP) control group. Overall, our results showed that PTSD participants displayed increased amygdala activation to surprised faces and may interpret them as a potential threat. Our results also suggest that individuals with PTSD respond more negatively to neutral facial expressions than the TENP group and that neutral facial expressions may be interpreted as a potential threat in PTSD. read less